Nagai's original Cutey Honey science-fiction action manga debuted in Akita Shoten's Weekly Shōnen Champion magazine from 1973 to 1974. The series has received various anime and manga adaptations, remakes, and sequels, as well as a live-action television series in 2007. Nagai's original Devilman Lady manga, related to his action horror manga Devilman, ran in Kodansha's Morning magazine from 1997 to 2000.

Nagai and his Dynamic Pro studio also launched the Devilman spinoff manga series Sirene-chan (pictured right) in Nihonbungeisha's Comic Heaven magazine last August.